Transductional analysis of the organization of genes involved in catabolic pathways in Pseudomonas putida indicates that an extensive degree of supraoperonic clustering exists. This project will attempt to determine if there are any biosynthetic functions located in this region of the chromosome, and the relationship between this cluster and various plasmids which carry genes of the same type. In addition, we will elucidate by enzyme assays and mutant isolation, the details of control of the expression of genes coding for enzymes of nicotinate and of proline and ornithine dissimilation in P. putida. By reverting polar mutants we hope to obtain strains carrying nonsense suppressors, which can then be used to demonstrate the protein nature of the products of regulatory genes in Pseudomonas. Partial diploids of catR will be constructed and the dominance relationships of various alleles studied.